Abstract
Determination of the phases arising at the interface between lead-free Sn3.5Ag0.4Cu29.5In solder and copper substrate after wetting of copper at 280 °C for 1800 s is presented. Compared are results obtained with methods of scanning electron microscopy (SEM) equipped with EDX analyser, X-ray diffraction and X-scan X-ray diffraction method. Standard X-ray diffraction profile shows the existence of four phases In0.2Sn0.8, Cu₆Sn₅, In₃Sn and Ag₃Sn. X-scan X-ray diffraction profile shows the presence of two phases at the interface In0.2Sn0.8 and Cu₆Sn₅ and adjacent phase to the copper substrate is In0.2Sn0.8 phase. Comparison of both methods is discussed.

Key words
X-scan, lead-free solder, copper, interface, phase analysis

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